getopt(1) [freebsd man page]
GETOPT(1) BSD General Commands Manual GETOPT(1) NAME
getopt -- parse command options SYNOPSIS
args=`getopt optstring $*` ; errcode=$?; set -- $args DESCRIPTION
The getopt utility is used to break up options in command lines for easy parsing by shell procedures, and to check for legal options. Optstring is a string of recognized option letters (see getopt(3)); if a letter is followed by a colon, the option is expected to have an argument which may or may not be separated from it by white space. The special option '--' is used to delimit the end of the options. The getopt utility will place '--' in the arguments at the end of the options, or recognize it if used explicitly. The shell arguments ($1 $2 ...) are reset so that each option is preceded by a '-' and in its own shell argument; each option argument is also in its own shell argu- ment. EXIT STATUS
The getopt utility prints an error message on the standard error output and exits with status > 0 when it encounters an option letter not included in optstring. EXAMPLES
The following code fragment shows how one might process the arguments for a command that can take the options -a and -b, and the option -o, which requires an argument. args=`getopt abo: $*` # you should not use `getopt abo: "$@"` since that would parse # the arguments differently from what the set command below does. if [ $? -ne 0 ]; then echo 'Usage: ...' exit 2 fi set -- $args # You cannot use the set command with a backquoted getopt directly, # since the exit code from getopt would be shadowed by those of set, # which is zero by definition. while true; do case "$1" in -a|-b) echo "flag $1 set"; sflags="${1#-}$sflags" shift ;; -o) echo "oarg is '$2'"; oarg="$2" shift; shift ;; --) shift; break ;; esac done echo "single-char flags: '$sflags'" echo "oarg is '$oarg'" This code will accept any of the following as equivalent: cmd -aoarg file file cmd -a -o arg file file cmd -oarg -a file file cmd -a -oarg -- file file SEE ALSO
getopts(1), sh(1), getopt(3) HISTORY
Written by Henry Spencer, working from a Bell Labs manual page. Behavior believed identical to the Bell version. Example changed in FreeBSD version 3.2 and 4.0. BUGS
Whatever getopt(3) has. Arguments containing white space or embedded shell metacharacters generally will not survive intact; this looks easy to fix but is not. Peo- ple trying to fix getopt or the example in this manpage should check the history of this file in FreeBSD. The error message for an invalid option is identified as coming from getopt rather than from the shell procedure containing the invocation of getopt; this again is hard to fix. The precise best way to use the set command to set the arguments without disrupting the value(s) of shell options varies from one shell ver- sion to another. Each shellscript has to carry complex code to parse arguments halfway correctly (like the example presented here). A better getopt-like tool would move much of the complexity into the tool and keep the client shell scripts simpler. BSD
January 26, 2011 BSD
Check Out this Related Man Page
getopt(1) User Commands getopt(1) NAME
getopt - parse command options SYNOPSIS
set -- ` getopt optstring $ * ` DESCRIPTION
The getopts command supersedes getopt. For more information, see NOTES below. getopt is used to break up options in command lines for easy parsing by shell procedures and to check for legal options. optstring is a string of recognized option letters; see getopt(3C). If a letter is followed by a colon (:), the option is expected to have an argument which may or may not be separated from it by white space. The special option - is used to delimit the end of the options. If it is used explicitly, getopt recognizes it; otherwise, getopt generates it; in either case, getopt places it at the end of the options. The posi- tional parameters ($1 $2 ...) of the shell are reset so that each option is preceded by a - and is in its own positional parameter; each option argument is also parsed into its own positional parameter. EXAMPLES
Example 1: Processing the arguments for a command The following code fragment shows how one might process the arguments for a command that can take the options -a or -b, as well as the option -o, which requires an argument: set -- `getopt abo: $*` if [ $? != 0 ] then echo $USAGE exit 2 fi for i in $* do case $i in -a | -b) FLAG=$i; shift;; -o) OARG=$2; shift 2;; --) shift; break;; esac done This code accepts any of the following as equivalent: cmd -aoarg filename1 filename2 cmd -a -o arg filename1 filename2 cmd -oarg -a filename1 filename2 cmd -a -oarg -- filename1 filename2 ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ |CSI |enabled | +-----------------------------+-----------------------------+ SEE ALSO
intro(1), getopts(1), getoptcvt(1), sh(1), shell_builtins(1), getopt(3C), attributes(5) DIAGNOSTICS
getopt prints an error message on the standard error when it encounters an option letter not included in optstring. NOTES
getopt will not be supported in the next major release. For this release a conversion tool has been provided, namely, getoptcvt. For more information, see getopts(1) and getoptcvt(1). Reset optind to 1 when rescanning the options. getopt does not support the part of Rule 8 of the command syntax standard (see intro(1)) that permits groups of option-arguments following an option to be separated by white space and quoted. For example, cmd -a -b -o "xxx z yy" filename is not handled correctly. To correct this deficiency, use the getopts command in place of getopt. If an option that takes an option-argument is followed by a value that is the same as one of the options listed in optstring (referring to the earlier EXAMPLES section, but using the following command line: cmd -o -a filename getopt always treats it as an option-argument to -o; it never recognizes -a as an option. For this case, the for loop in the example shifts past the filename argument. SunOS 5.10 7 Jan 2000 getopt(1)